Heat-dissipating accessory plate for high speed drilling

ABSTRACT

A heat-dissipating accessory plate for high speed drilling, prepared by adhering a composite material which is a solid state, abrasion-resistant, lubricating coating comprised of nano-structure powder and a high heat-conducting compound, over a supporting material, and then covering a lubricating layer over said composite material, can provide an action of grinding and lubricating a drill bit as well as dissipate heat generated during drilling processing on a printed circuit board.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a cover plate useful for printed circuit board(PCB), and more particularly to a heat-dissipating accessory plate forhigh speed drilling comprised of a composite material, it can exhibitactions of grinding, lubricating drilling bit and heat conducting duringdrilling processing.

2. Description of the Prior Art

In recent years, as the electronic technology progresses with eachpassing day, and many high technical industries develops successively, agreat number of more humanized new electronic products having betterfunctions have been developed constantly toward a trend of lower weight,thinner, shorter and smaller size. Every electronic product hasgenerally at least one main board comprised of many electronic elementsand circuit board. The function of a circuit board comprises ofsupporting and electrically connecting electronic elements so that thoseelectronic elements can function properly. Currently, circuit boardsmost commonly used are printed circuit board (PCB).

A printed circuit board can link electronic components together suchthat the integral function of these electronic components electricallyconnected can be realized. Therefore, PCB is an indispensablefundamental element in all of the electronic informational products.Since printed circuit board may have uneven, some good and some baddesigns, which may not only affect directly the reliability of anelectronic product, but also can influence the competitiveness of asystem product, it is often referred as “the mother of an electronicsystem product” or “the base of 3C industry”. PCB is a flat board madeof a non-conducting material. On this board, there is intended to drillholes for mounting chips or other electronic elements. These holes forelements can facilitate the electrical connecting of defined metalroutes previously printed over the board, whereby connecting legs ofthese electronic elements penetrate PCB, and are adhered then on the PCBwith conducting metal solder to form an electrical circuit.

However, during drilling the circuit board, for holes of small diameter,a correspondingly small drill bit must be used, which, consequently,results in frequent drill bit breaking. The common method for drillingholes on PCB is that PCB comprises a aluminum cover plate (as shown inFIG. 3) in order to buffer the drill bit and dissipate heat therefromduring drilling. Said aluminum cover plate (3) is generally consisted ofan aluminum foil (32), a porous fiber layer (31) and a lubricating layer(33).

Further, during drilling, since the porous fiber layer (31) is in solidstate and insoluble, borings produced in the drilling hole often breaksthe drill bit or roughens the inner wall of the drill hole in the PCB.

Furthermore, since the rotational rate of the drill bit must beincreased in order to accelerate the drilling speed, and as the result,the porous fiber layer (31) is fail to dissipate efficiently the heatproduced by the drill bit (4) in the friction of such high speeddrilling, the use life of the drill bit might be reduced consequently.

Moreover, during drilling, the insufficient lubrication of the drill bit(4) by the aluminum foil (32) of said aluminum cover plate (3) tends toresult in scattering a lot of metal borings over the PCB under the highspeed drilling. These borings might, if not cleaned up, incur anelectrical short-circuit in the use of the PCB, and hence affect thereliability of the product.

SUMMARY OF THE INVENTION

One objective of the invention is to provide a heat-dissipatingaccessory plate for high speed drilling on PCB, it has simplecomposition and low cost.

Another objective of the invention is to provide a heat-dissipatingaccessory plate for high speed drilling, it can provide both actions ofgrinding and lubricating the drill bit during drilling.

The another objective of the invention is to provide a heat-dissipatingaccessory plate for high speed drilling, it can avoid the roughening ofthe inner wall of the drill hole or the breaking of the drill bit.

Still another objective of the invention is to provide aheat-dissipating accessory plate for high speed drilling, it can conductefficiently heat from the drill bit.

In order to achieve the above-mentioned objectives of the invention, theheat-dissipating accessory plate for high speed drilling according tothe invention comprises a supporting material, a composite material anda lubricating layer, wherein said composite material is a solid state,abrasion-resistant lubricating coating consisted of nano-structurepowder and a highly heat-conducting compound, the said compositematerial is adhered on said supporting material, and said lubricatinglayer is coated over said composite material, thereby during drillingprocess, the purpose of the lubrication and heat dissipation of thedrill bit can be achieved by means of the above-describedheat-dissipating accessory plate for high speed drilling.

In order to better understand the invention, it will be described moredetail with reference of the following embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a heat-dissipating accessory plate forhigh speed drilling of the invention;

FIG. 2 is a sectional view illustrating the use of a heat-dissipatingaccessory plate for high speed drilling of the invention on the PCBduring drilling; and

FIG. 3 is a sectional view of a drilling cover plate of prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a heat-dissipating accessory plate for high speeddrilling (1) according to one preferred embodiment of the inventioncomprises a supporting material (13), a composite material (11) and alubricating layer (12).

Said composite material (11) is a solid state, abrasion-resistantlubricating coating consisted of nano-structure powder and a highlyheat-conducting compound, wherein said composite material is adhered onsaid supporting material (13). In a preferred embodiment of theinvention, said nano-structure powder may be one or more powder selectedfrom the group consisting of molybdenum disulfide (MoS₂) nano-particles,tungsten disulfide (WS₂) nano-particles, copper disulfide (CuS)nano-particles, aluminum oxide (Al₂O₃) nano-particles, lanthanidefluoride (LaF₃) nano-particles, silicon carbide (SiC) nano-particles,silicon nitride (Si₃N₄) nano-particles, silicon dioxide (SiO₂)nano-particles, borate nano-particles, and metal nano-powder. Saidhighly heat-conducting compound may be one or more compound selectedfrom the group consisting of aluminum hydroxide (Al(OH)₃), boron nitride(BN) or aluminum nitride (AlN), which can dissipate the heat generatedduring the drilling process so as to reduce the effect of the frictionheat generated during drilling on the material of the printed circuitboard (2) and to extend the use life of the drill bit.

Said lubricating layer (12) is coated on the surface of theabove-described composite material (11). In a preferred embodimentaccording to the invention, said lubricating layer (12) is one or moresubstances selected from the group consisting of nonyl phenolpolyethylene glycol ether, polyethylene glycol (PEG), polyvinyl alcohol(PVA), polyacrylic acid and its salts thereof, poly methyl methacrylate(Perspex), cerotic acid, isopropyl cinnamate, glycerol monostearate, beewax and mixture thereof.

Said supporting material (13) may be a plastic plate or a metal foil. Ina preferred embodiment, said supporting material (13) is plasticmaterial. Said supporting material (13) is used to support theabove-described composite material (11) and lubricating layer (12). Asborings produced from said supporting material (13) during drilling is,unlike conducting metal, electrical non-conducting, problems such aselectrical short circuit or burn out during the use of a printed circuitboard (2) can be avoided.

Thus, as shown in FIG. 2, in the practice of the invention, the thusfinished heat-dissipating accessory plate for high speed drilling (1) isplaced over the printed circuit board (2) to carry out drilling process.As the drilling apparatus reaches a pre-determined drilling position,the drill bit (4) is lowered and performs drilling operation. As thedrill bit (4) is lowered, it will penetrate the lubricating layer (12)provided by the invention, whereby the drill bit (4) could be lubricatedand its penetrating force could be buffered such that the deviation of ahole or breaking of drill bit can be avoided. As the drill bit (4) islowered further, it will pass through the composite material (11)provided by the invention, wherein said composite material (11) iscomprised of nano-structure powder and wherein, owing to the specialstructure from said nano-structure powder, there are four effects,namely, quantum-size effect, macro-quantum tunnel effect, surface effectand volume effect, and hence it can exhibit both features of lubricationand abrasion resistance, and can exert simultaneously actions ofgrinding and lubricating the drill bit (4) so as to keep the drill bitsharp. Meanwhile, the highly heat-conducting compound contained in thecomposite material can carry away in time the heat generated during highrotation of the drill bit (4).

When the drill bit is lowered further, it will penetrate through thesupporting material (13) of the invention. In preferred embodimentsaccording to the invention, said supporting material (13) is a plasticplate. As the drill bit penetrates through said supporting material(13), plastic borings thus generated is electrical non-conducting ratherthan electrical conducting like metal so that the short circuit orburnout occurred in the use of the printed circuit board (2) can beavoided.

Therefore, the invention has following advantages:

-   1. The invention provides a heat-dissipating accessory plate for    high speed drilling suitable for drilling processing on a printed    circuit board, it has a simple composition and low cost.-   2. The invention provides a heat-dissipating accessory plate for    high speed drilling, wherein its composite material comprises a    highly conducting compound that can carry away the heat generated    during drilling so as to achieve the heat dissipating effect.-   3. The invention provides a heat-dissipating accessory plate for    high speed drilling, wherein its composite material comprises    nano-structure powder that can grind and lubricating the drill bit    during drilling.-   4. The invention provides a heat-dissipating accessory plate for    high speed drilling, characterized in that, with its structure    comprising a solid state abrasion-resistant lubricating layer, it    can avoid the generation of borings during drilling, and hence can    prevent the inner wall of the drilled part from roughening as well    as can avoid the breaking of the drill bit.-   5. The invention provides a heat-dissipating accessory plate for    high speed drilling, wherein it comprises a supporting material    characterized in that said supporting material is a plastic plate    that can not only decrease effectively the production cost, but    also, owing to its electrical non-conducting feature, the metal    borings generated from the prior art drilling cover plate can be    eliminated, that is, during drilling processing, no such metal    borings would be produced and hence no electrical short circuit    would take place. Further, even if the supporting material used in    the heat-dissipating accessory plate according to the invention    comprises a metal foil, the drilling hole can achieve good    lubrication by virtue of the double-layer lubrication design based    on both of the lubricating layer and the solid state    abrasion-resistant lubricating coating, such that, during drilling,    metal borings can be prevent from sputtering around.

Accordingly, based on the above disclosure and drawings, the objectivesaccording to the invention can be achieved by providing aheat-dissipating accessory plate for high speed drilling characterizedin that it can avoid the generation of borings during drillingprocessing and meanwhile can conduct and dissipate heat generated. Whilethe invention has been described with reference to embodiments andtechnical means thereof, various change and modification can be madebased on the disclosure or teachings described herein. Those equivalentchange made based on technical means of the invention having theireffect without departing from the spirit encompassed by thespecification and drawings are intended to be fallen within the scope ofthe invention defined only by the appended claims.

1. A heat-dissipating accessory plate for high speed drilling, usefulplacing over a printed circuit board during drilling, comprises: acomposite material, which is a solid state, abrasion-resistantlubricating coating consisted of nano-structure powder and a highlyheat-conducting compound; a supporting material, for adhering andsupporting said composite material, and a lubricating layer, providedover the surface of said composite material; whereby, during drillingprocessing on the printed circuit board, said drill bit can be groundand lubricated, while the heat generated can be dissipated.
 2. Theheat-dissipating accessory plate for high speed drilling as claimed inclaim 1, wherein said supporting material is a plastic plate.
 3. Theheat-dissipating accessory plate for high speed drilling as claimed inclaim 1, wherein said supporting material is a metal foil.
 4. Theheat-dissipating accessory plate for high speed drilling as claimed inclaim 1, wherein said lubricating coating is one or more substancesselected from the group consisting of nonyl phenol polyethylene glycolether, polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyacrylicacid and salts thereof, poly methyl methacrylate (Perspex), ceroticacid, isopropyl cinnamate, glycerol monostearate, bee wax and mixturethereof.
 5. The heat-dissipating accessory plate for high speed drillingas claimed in claim 1, wherein said highly heat-conducting compound isone or more compound selected from the group consisting of aluminumhydroxide (Al(OH)₃), boron nitride (BN) and aluminum nitride (AlN). 6.The heat-dissipating accessory plate for high speed drilling as claimedin claim 1, wherein said nano-structure powder is one or more powderselected from the group consisting of molybdenum disulfide (MoS₂)nano-particles, tungsten disulfide (WS₂) nano-particles, copperdisulfide (CuS) nano-particles, aluminum oxide (Al₂O₃) nano-particles,lanthanide fluoride (LaF₃) nano-particles, silicon carbide (SiC)nano-particles, silicon nitride (Si₃N₄) nano-particles, silicon dioxide(SiO₂) nano-particles, borate nano-particles, and metal nano-powder.